Compounds and compositions capable of evolving oxygen and absorbing carbon dioxide are presently in demand for use in closed-circuit emergency breathing devices. Such compounds are a desirable alternative to heavy, bulky air or oxygen cylinders with canisters containing caustic alkali or soda lime for carbon dioxide removal. Compounds presently employed for this use include compounds of boron, oxygen and alkaline earth metals or alkali metals, especially sodium, potassium and lithium. For example, U.S. Pat. No. 4,238,464 discloses several air revitalization compounds or compositions, containing alkali metal or alkaline earth hydroxides, peroxides, superoxides and mixtures thereof. Lithium compounds disclosed in that patent include (LiOH).sub.2.LiBO.sub.5 ; (LiOH.Li.sub.2 O.sub.2).sub.2.Li.sub.3 B.sub.3 O.sub.13, and (Li.sub.2 O.sub.2).sub.2.Li.sub.2 B.sub.2 O.sub.8. The compounds of that patent contain 10 to 22%, by weight, effervescent oxygen, with the lithium compounds containing 16 to 20% effervescent oxygen. The compounds also contain between 6 to 15%, by weight, of peroxide oxygen. The '464 patent also teaches that the preparation of the oxygen-generating compounds requires slow dehydration in very high vacuum at low temperatures. The major portion of the dehydration takes place at temperatures of 8.degree. C. or lower and under an extremely high vacuum of only 3-5 microns Hg over a period of 8 to 10 days. Only after the reactions and dehydration are essentially complete is the temperature allowed to rise to 23.degree.-25.degree. C.
From the standpoint of commercial production the use of such high vacuums, and especially over many days, is undesirable. Furthermore, the maintenance of very low temperatures, especially in view of the exothermicity involved, over many days adds significant expense to commercial production.
There is thus a need in the art for compositions which are inexpensive, readily obtainable and stable, and have a high rate of carbon dioxide absorption and of oxygen evolution.